


An Experiment or Whatever

by what_should_i_post_here



Category: Teenage Mutant Ninja Turtles (TV 2012), Teenage Mutant Ninja Turtles - All Media Types
Genre: Blow Jobs, Dirty Talk, Experimentation, Interspecies Sex, M/M, Oral Sex, Plot What Plot/Porn Without Plot, Turtlecest, Weirdness
Language: English
Status: Completed
Published: 2018-05-20
Updated: 2018-05-20
Packaged: 2019-05-09 12:26:36
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,841
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14716026
Author URL: https://archiveofourown.org/users/what_should_i_post_here/pseuds/what_should_i_post_here
Summary: After catching Raph and Donnie together, Casey gets a little curious...and hands-y.





	An Experiment or Whatever

**Author's Note:**

> What is this mess???
> 
> Oh, it's just me attempting to write another Jonatello fic. It's so bad, but it's kinda fun. It's smut, you know the drill
> 
> WILL FIX ANY ERRORS LATER

"Hey, Donnie!" Casey called out, strolling into the genius turtle's lab. "I was just wondering if-"

Suddenly, he froze, taking in the scene before him. Donnie, on his knees in front of Raph. Raph's hands on Donnie's head, pushing him closer to his... "Oh!" Quickly the teenage boy turned around, his face burning.

"D-Damn it, Casey, what the hell?" Raph muttered angrily. There was a bit of struggle in his voice, which Casey assumed was from him pulling away from Donnie.

"Dudes," Casey mumbled, still facing the other way. "I seriously had no idea you guys were...I-I was just looking for Don!"

"Well, ya found him!" 

There was a brief moment between the two turtles that sounded like an apology from Donnie, which Raph brushed off, running from the lab, hands covering his crotch.

After a moment, the boy spoke up. "Is, uh, is the coast clear?"

Donnie sighed, wiping his mouth and heading back to his desk. "Yeah, Casey. You're good."

Carefully, Casey removed his hands away from his eyes and turned around. "Yo, I am so sorry about that. I didn't realize-"

"Was there something you needed?" Donnie interrupted, pulling the goggles still on his head down so they were covering his eyes.

"I uh..." Casey chuckled nervously. "I can't really remember right now. All I can think about is..."

Donnie glared.

"I mean, I knew all you were...together, I just never realized...I mean, you guys have dicks?"

Donnie gave another exasperated sigh. "Yes, Casey, we have dicks. How else would we have sex?"

"Yo, geez!" Casey closed his eyes and threw his hands out in front of him, waving them back and forth at the very thought. "Guess I never really thought about it before."

The tech turtle actually smirked before returning to his work. "Okay well, let me know if you remember what you even wanted."

There was a brief silence that Donnie almost mistook for Casey actually leaving him alone, when the teen suddenly spoke up again.

"So...where is it?"

"Where is what?"

"Your dick," He continued, and the wrench in Donnie's hand slipped. "I mean, you said you guys have 'em, but you don't even wear pants, so you'd think that-"

"Casey!"

"Just curious," He shrugged. "I know I caught ya in the act, but...I couldn't really tell before, ya know? Cause your head was kinda blocking Raph's-"

"Okay, okay!" Donnie's face was burning. Then after a moment, it subsided. "If I tell you, will you leave me alone?"

"Of course!"

"And will you _promise_ to **knock** next time you need something?"

"Obviously," He said with a snort.

"Okay," Donnie began, pulling his goggles back up. "They're uh..." He cleared his throat. "They're hidden beneath the crotch area of our plastrons." The genius gestured downwards. "When we get...aroused, the cartilage there becomes softer, allowing them to...drop down."

Casey blinked. "What? Really??"

"Yes."

"That a real turtle thing or...?"

"It's a mutation thing," Donnie answered. "With actual turtles, the appentage comes out from its tail."

Another brief pause and Casey started laughing. "That's hilarious."

He frowned. "Alright well...I told you, so if you don't mind-"

"Can I see it?"

Both boys froze. Donnie's hand stilled on goggles, looking at Casey through only his peripheral vision. The teen also seemed a little embarrassed by his outbursted question.

"Wha...of course not!"

"Come on," Casey suggested, feeling a little more bold. "We can make it fair. Show me yours, I'll show you mine?"

"I don't want to see that."

Casey smirked. "Think of it as an experiment. Er, research. Whatever you call it."

"Absolutely not."

"Afraid I might be bigger than you?"

Donnie almost smiled. "Trust me, you're not."

"What makes you so sure?" Casey insisted. "Ever seen a man's dick before?"

"It's nature, Casey," Donnie said. "Biologically, turtles are-"

"But you ain't a full turtle, are ya, Donnie?"

Donnie looked up to find the challenging stare Casey Jones looking back at him. "Fine." He pushed his chair back and stood up, hands already removing his belt.

"We actually doing this?"

"We're not _doing_ anything," Donnie insisted. "You want to see a turtle penis, you're going to see a turtle penis."

"Dude, just say dick."

"Fine," Donnie looked right at Casey and smirked. " _Dick_."

The genius then closed his eyes and ran a hand down his plastron. After a few moments of petting around his crotch, the cartilage began opening up into a slit. Casey was close enough that he could just make out the obvious bulbous head of Donnie's cock beginning to peek through, and after another blink, it was lying in the turtle's three-fingered hand.

And Donnie was absolutely right. Even only half hard, his dick was already larger than Casey's. He felt as though he should be upset or embarrassed by that, but couldn't really feel anything, eyes too transfixed on what was right in front of him.

Donnie was both amused and slightly freaked out by Casey's reaction. It wasn't like the teenager to be quiet this long.

"Well?"

"You, uh..." The teen licked his dry lips, attempting to form words. "Y-you were right."

"I know." Donnie smirked proudly. "So you gonna show me yours or what? Casey?"

The teen only shook his head, then suddenly, he was crawling out of his chair, and moving closer to the turtle.

"Whoa, what are you doing?" Donnie started backing up slowly, but Casey continued forward. "Come on, Jones. You're freaking me out."

"Ever given a blowjob before?"

The turtle frowned. "You know I have."

"Ever gotten one before?"

"O-obviously."

"By a human?"

Donnie was only slightly taken back by Casey's insinuation. He smirked. "Now you and I both know a human couldn't handle that."

Then Casey smiled darkly, as if that was exactly what he wanted to hear. "Challenge accepted."

Then, with no further warning, Casey dropped down onto his knees, wrapping his own hand alongside Donnie's around the large, green cock.

"Holy shi-" Donnie began, cutting his curse off with his hand.

Casey looked amused and carefully explored the hardening appendage now that Donnie's large hand was gone from it.

"Casey, cut it out!" The genius whispered harshly. "This isn't funny anymore."

"Wasn't meant to be funny."

"What if someone catches us?"

"Maybe they'll join in," He winked.

"That's not what I-" Donnie began, interrupting himself with a loud moan when Casey's tongue touched the side of his cock.

Casey did it again, licking the opposite side and Donnie threw his head back with a groan.

When Casey's mouth wrapped around the head of his cock, the turtle almost collapsed to the ground. Thankfully he wasn't too far from his abandoned swivel chair and with just the right angling, he managed to fall into it, without taking Casey away from his current task.

Donnie didn't really know why, but being sucked by Casey was so much different than with his brothers.

Maybe it was his nose. The way the point of it pressed right into his skin as Casey took a long lick up his shaft. Or how the hot air wafted from his nostrils across the base of his cock, as Casey attempted to deep throat him.

Or maybe it was his skin, not at all similar to the green, smooth yet scaly skin he was used to. Donnie never really noticed it before, but now, holding the teens head in place as he continued to down his cock, his hands felt what he couldn't see.

Casey didn't have a beard, but Donnie could tell due to the slight prickle at his cheeks and upper lip that he was close to getting one. Or perhaps he shaved it.

It gave a surprisingly wonderful feeling against his hands and feeling curious, Donnie forced the teen off his rod for a second and rubbed the leaking appendage all over the human's cheeks and mouth, revelling in the rough feeling of it.

Casey stopped the movement quickly by wrapping a fist around the base of the cock and Donnie groaned.

The turtle looked down at Casey's admonished expression, precum almost dripping from the boy's chin. The genius bit his lip, his face burning in silent apology.

After a moment, Casey chuckled. "Like it sloppy, huh, D?"

"Oh, I-I...I didn't..."

"Wanna shoot your hot cum all over me?"

Donnie bit back a churr. Hearing someone other than his brothers attempt dirty talk was surprisingly arousing.

"I figured you'd just want me to drink it all down, but I bet that's more Raph's thing, huh?" Casey continued on, taking short licks between sentences. "You like to see your work right in front of you. Wanna see your cum drip down my face, onto the floor of your lab."

"Casey..."

"Yeah, you like that?" The teen smirked, his hand becoming a blur on Donnie's cock. "You're kinkier than I would have guessed, D. Bet you'd like to watch me lick it up, too, huh? Lick your cum right off the floor like a freaking pet or something."

"Fuck..." Donnie moaned, his hand joining Casey's, helping the boy pump him to completion.

"Or maybe you'd rather leave it there till it stains," Casey continued, his voice becoming louder, so he could still be heard over Donnie's constant moaning. "So you can look back on it. Like some dirty masterpiece or something? You _are_ named after an artist, after all."

"Hah," Donnie groaned. He couldn't believe how hot Casey was sounding right now. **Casey Jones**. Single-handledly the most annoying human being he'd ever met (after Baxter Stockman, maybe) was sucking his dick. Turning him into a blubbering hot mess. He'd never wanted to cum so badly in his entire life.

"Paint me, Don," Casey ordered, a sick smile on his face. "Paint me with your white cum! Paint me like a fucking-"

Before the teen could even finish, Donnie did just that, coming all over Casey. He held onto his cock long after the teen had let go, using it like a wand, pointing it wherever he pleased. At Casey's face, his hair, his bandana, his shirt...

When he finally finished, he slumped backwards onto his chair, breathing hard.

"Fuck, dude..." Casey mumbled from the floor.

Opening his eyes, Donnie looked down to find Casey had unzipped just the front of his jeans so his cock could break free. He was just about to grab onto it when Donnie leaned down and pulled the boy up, latching onto his lips like he was staving.

He took extra care in sucking his own essence from Casey's lips, forcing them both to taste him when he stuck his tongue in the teen's mouth.

"Damn..." Casey said when they finally separated.

Donnie gave a breathy chuckle. "That a good enough 'experiment' for you?"

"Yeah," Casey chuckled, taking off his soiled bandana. "So you're more of a...hands-on kinda scientist, huh?"

Donnie considered this, eyes darting down to Casey's exposed cock and back to his face. "Guess you're about to find out," He said, licking his lips.


End file.
